Multiple sensor data processor interface and relay

ABSTRACT

The present invention relates generally to a system and method of networking and interconnecting a large number of various types of sensors to a remote location in an efficient manner. Specifically, the invention utilizes a flexible, configurable, scalable and power-efficient sensor interface relay architecture to gather sensor data from various locations and then relay it to a remote location via the internet.

FIELD OF THE INVENTION

The present invention relates generally to a system and method ofnetworking and interconnecting a large number of various types ofsensors to a remote location in an efficient manner. Specifically, theinvention utilizes a flexible, configurable, scalable andpower-efficient sensor interface relay architecture to gather, process,and analyze sensor data from various locations and then relay it to aremote location via the internet.

BACKGROUND OF THE INVENTION

A wide variety of sensor types are required to monitor assets like anoffice building, a store or a large campus. In addition, a number ofthese sensors are required for monitoring large assets. It is thereforepreferred to have very low cost sensors. The sensor data must typicallybe processed, analyzed, and communicated to a remote location forfurther analysis. Communicating sensor data over long distances by wiresis very cumbersome, prone to damage and comes with a high cost ofinstallation and time. On the other hand, having wireless communicationcapabilities in each sensor is highly cost prohibitive and powerinefficient. Moreover, there are a large number of sensor electricalinterfaces that are different from each other.

To solve the problem of connecting a large number of different sensortypes of sensors to a remote location in an efficient manner, a highlyflexible, configurable, scalable and power efficient sensor interfacearchitecture has been devised. Multiple sensors with a wide variety ofelectrical interfaces in a localized area can be connected by wire to aunit called the Sensor Interface Relay (SIR) that hosts the flexiblesensor interface architecture.

The SIR can gather data from multiple sensors, process and analyze thedata, and then relay the data to a remote location via wired or wirelesscommunications as needed. In order to do this, the SIR architectureallows multiple sensors with different electrical interfaces to beconnected to it via sensor ports. The data analysis is performed by thefirst processing unit (the main micro-controller PSoC5). Themicro-controller has an embedded ARM Cortex M3 CPU that is used toanalyze the sensor data and also perform other functions. Commerciallyavailable or custom software can be used to calculate statistical orapplication-specific analytics on the first processing unit. Thearchitecture is highly flexible by allowing any of the supported sensorinterfaces to be connected to any sensor port in any combination. It ishighly configurable by allowing any of the sensor ports to be programmedto interface with any supported sensor. The architecture can be easilyscaled to support a large number of sensors using one SIR. By beingpower efficient, the SIR can operate on battery power without the needfor battery replacement for a long time.

SUMMARY OF THE INVENTION

The Sensor Interface Relay (SIR) is directed to a system and method ofnetworking and interconnecting a large number of various types ofsensors to a remote location in an efficient manner. Specifically, theSIR utilizes a flexible, configurable, scalable and power-efficientsensor interface relay architecture to gather, process and analyzesensor data from various locations and then relay it to a remotelocation via the internet.

A first aspect of the invention is a method of obtaining inputs from aplurality of sensor coupling ports. The method includes a firstprocessing unit communicating a state change on a first commonaddressing signal coupled to each of a plurality of second processingunits and uniquely addressing one of the plurality of second processingunits on at least one additional addressing signal. The first processingunit also communicates a state change on a common enable signal coupledto each of the plurality of second processing units. One of theplurality of second processing units detects the state change on thefirst common addressing signal, the unique addressing, and thesubsequent state change on the common enable signal line and enablescommunication from the first processing unit to the one uniquelyaddressed second processing unit to enable a sensor coupling portcoupled to the uniquely addressed second processing unit to receiveinput. Input is subsequently received to the first processing unit fromthe sensor coupling port.

Additional aspects of the method include uniquely addressing one of theplurality of second processing units by addressing the second processingunits over a plurality of addressing signals respectively coupled toeach of the second processing units. The uniquely addressed secondprocessing unit may communicate to sensor interface circuitry tocommunicate over the sensor coupling port in a standard selected fromRS232, RS485, UART, Open Collector, Open Drain, I2C, Maxim 1-Wire,Analog AC voltage, Analog DC voltage, Analog Resistance, CMOS, and TTL.It is a further aspect to eliminate power from the non-uniquelyaddressed remaining plurality of second processing units. A furtheraspect includes uniquely addressing a second of the plurality of secondprocessing units, subsequently initiating a state change on the commonenable signal line coupled to each of the plurality of second processingunits, and detecting both the unique addressing and the subsequentlyinitiated state change on the common enable signal line in the second ofthe plurality of second processing units, and communicating from thefirst processing unit to the second uniquely addressed second processingunit to receive input from the second sensor coupling port. And thesecond uniquely addressed second processing unit may communicate to asecond sensor interface circuit to communicates over the second sensorcoupling port in a standard selected from RS232, RS485, UART, OpenCollector, Open Drain, I2C, Maxim 1-Wire, Analog AC voltage, Analog DCvoltage, Analog Resistance, CMOS, and TTL. Another aspect includessourcing a sensor power supply signal to one of the plurality of sensorcoupling ports prior to communicating the state change on the firstcommon addressing signal. Another aspect includes that the plurality ofsensor coupling ports are unpowered and receipt of sensor input isinitiated on receipt of an interrupt received from the sensor couplingport. Alternatively, the sensing operations may be initiated atprogrammed intervals. Another aspect includes enabling sensor interfacecircuitry such as an RS232 or RS485 transceiver or a root mean square toDC voltage converter to communicate with the sensor coupling port. Anadditional aspect includes eliminating power to the plurality of secondprocessing units and transmitting received input to at least one remotehardware and software system.

Aspects of the invention are implementable in a sensing interfacecircuit comprised of a first processing unit having outputs including afirst common enable signal, a plurality of addressing signals, andplurality of individual enable signals. A plurality of second processingunits are each coupled to processor memory containing configurationprogramming information to configure the sensing interface circuit toprovide power and communications over each of a plurality of sensorcoupling ports, each of the plurality of sensor coupling ports coupledto one of the plurality of first processing units, each sensor couplingport including at least one sensor voltage supply connection, and atleast one sensor receive input. The plurality of second processing unitsare each coupled to the first common enable signal and the plurality ofaddressing signals and each respectively connected to one of theplurality of individual enable signals to initiate receipt of input fromthe sensor coupling ports.

Another aspect of the sensing interface circuit includes a plurality ofcommunications sensor interface circuits selected from RS232transceivers, RS485 transceivers, and root mean square to DC voltageconverter circuits that are respectively coupled between the pluralityof second processing units and the plurality of sensor connection ports.Another aspect of the sensing interface circuit may include a sensortransmit output. A transmitter selected from GPS radio, Cellular radio,ZigBee radio, and a POTS transceiver, may be coupled to the firstprocessing unit to relay received input to a remote hardware andsoftware system.

The novel features of invention itself, both as to its structure and itsoperation together with the additional object and advantages will bestbe understood from the following description of the preferred embodimentof the system. Unless specifically noted, it is intended that the wordsand phrases in the specification and claims be given the ordinary andaccustomed meaning to those of ordinary skill in the applicable art orarts. If any other meaning is intended, the specification willspecifically state that a special meaning is being applied to a word orphrase. Likewise, the use of the words “function” or “means” in theDescription of Preferred Embodiments is not intended to indicate adesire to invoke the special provision of 35 U.S.C. §112, paragraph 6 todefine the invention. To the contrary, if the provisions of 35 U.S.C.§112, paragraph 6 are sought to be invoked to define the invention(s),the claims will specifically state the phrases “means for” or “step for”and a function, without also reciting in such phrases any structure,material, or act in support of the function.

Moreover, even if the provisions of 35 U.S.C. §112, paragraph 6 areinvoked to define the inventions, it is intended that the inventions notbe limited only to the specific structure, material or acts that aredescribed in the preferred embodiments, but in addition, include anystructures, materials or acts that perform the claimed function, alongwith any and all known or later developed equivalent structures,materials, or acts for performing the claimed function.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram showing components of an SIRimplementation according to the description.

FIG. 2 is a power domain architecture block diagram.

FIG. 3 illustrates a timing diagram describing the process of providingpower to the SIR;

FIG. 4 illustrates a preferred SIR mode or state transition diagram;

FIG. 5 illustrates a block diagram of aspects of the connection betweenthe micro-processor 10 and the SIP 20, including the interface 22, thesensor interface circuitry 23, and the sensor coupling port 25;

FIG. 6 illustrates a process for sequentially enabling an SIP interface22 and the associated sensor interface circuitry 23 for a sensorcoupling port 25;

FIG. 7 illustrates a preferred embodiment of an SIP 20 wherein theinterfaces 22 share the addressing, and communications signals from andto the micro-controller 10;

FIG. 8 illustrates greater detail of a preferred SIP 20 embodiment andincludes sensor interface circuitry 23 in the form of a RS232/RS485communications transceiver and an root mean square to direct currentconverter; and

FIG. 9 illustrates a truth table of the configuration informationcommunicated from the preferred SIP 20 embodiment of FIG. 7.

FIG. 10 illustrates a block diagram showing several sensors receivingand transmitting data to the microcontroller.

FIG. 11 is a schematic of the power switches and multiplexers inside theSIP block that are controlled by the interface sensor port configurationprogramming stored within firmware.

FIG. 12 is a truth table showing the possible combinations of inputs andoutputs for the SIP block.

DESCRIPTION OF PREFERRED EMBODIMENT

A logical block diagram of aspects of the SIR architecture is shown inFIG. 1. This diagram is not representative of the entire functionalityof the SIR but provides a reference for describing the SIRs sensing andcommunication capabilities. The SIR embodiment includes various logicalfunctioning blocks including: a Micro-controller 10; a Power System 4; aSensor Interface Port (SIP) 20; a Cellular Radio (optional) 6; anAccelerometer 8; a Non-volatile Memory 12; a GPS Radio (optional) 14; aZigBee Radio (optional) 16; POTS (optional) 18; and an optional SensorExpansion Board 22. The illustrated SIR embodiment supports cellularlong haul communications and therefore includes a cellular radio forcommunications between the SIR and remote hardware and software systems.Short haul communication options however may be more practicalalternative for sensing applications that require multiple SIR devicesto communicate to remote hardware and software systems. In suchapplications, having dedicated cellular communications capabilities foreach SIR would be an expensive and less than optimal solution.Accordingly, the SIR embodiment may also include POTS and/or ZigBeeradio capabilities and if needed, separate GPS receivers for SIRembodiments that do not include cellular communications but that requireGPS capabilities.

Additional components shown in the functional block diagram include thediagnostic and VDC ports 7, and the power button and LED indicator 5.The diagnostic port can be used to retrieve data from the SIR device fordiagnostic purposes and can also be used to load firmware into thedevice. The VDC port acts as a DC power supply source to the device andalso charges the internal battery when connected. The power button andLED indicator informs the user when the device is initially powered up.In order to conserve battery life the LED indicator will not remain on.It will be turned on when the power button is pushed, to indicate thedevice has been powered up, but it will be shut off after a short timeperiod to conserve battery life.

The SIR power system design includes 3.3V and 5V supply voltages. Thepower supply domain diagram is shown in FIG. 2. The power system blockis supplied by either an internal battery or through an external DCport. The DC input voltage is expected to be provided by an adaptor thatproduces a 5V output nominally. The power system block contains abattery charger, a fuel gauge, and multiple regulator components. Thesecomponents generate the main supply voltage levels that are distributedto all the blocks in the system. Removing power from a block isperformed by either disabling a regulator or by disabling a power switchthat connects a regulated supply to the block. All blocks can be powereddown except the micro-controller 10. The micro-controller 10 must bepowered at all times since it contains the Real-Time-Clock (RTC) used togenerate the time based interrupts required for proper SIR operation.The micro-controller 10 is also responsible for setting up the signalinterfaces properly between powered and unpowered blocks.

A timing diagram describing the power supply sequence is provided inFIG. 2. The timing diagram includes the power supply control signalstates with respect to the mode of operation. If a block is to bepowered up the supply will be connected when transitioning from sleepmode to standby mode. The system remains in standby mode until all thesupplies and signal interfaces have stabilized. If a block will not beused its supply will not be enabled and the block remains unpowered.These scenarios are designated in the timing diagram by text associatedwith the signal waveform.

As mentioned, all blocks that will be used in the current mode sequenceare powered up during standby mode. Once the block supply levels havestabilized and the signal interfaces are properly set, the system isready to transition to the active mode. During active mode not allblocks will be functional. Only those blocks that are performingoperations will be enabled. The enabled blocks will consume activecurrent while the disabled blocks will consume standby current. Once ablock has completed its operation it will be disabled and the next blockin the chain will be enabled. This process continues until the cyclecompletes and the system returns to the sleep mode. This SIR powerstrategy minimizes the current consumed and saves on battery life but itrequires the sequence of events to be timed properly. Accordingly, theblocks can be powered up and enabled during standby mode and remainenabled until all operations have been completed.

SIR operation is governed by one or more software processes 300operating on the micro-controller 10 to place the SIR in one of severaloperational modes. Exemplary and preferred operational modes include:System Initialization; Sleep; Standby; Active; and Communication. Apreferred SIR mode transition and state diagram is shown in FIG. 4.

System Initialization 310—During system power-up the block power upsequence will be controlled and the pin interface states will be set inorder to ensure the SIR system powers up safely. SIP 20 communicationsconfiguration will also be performed during the initial system power up.All these operations occur during the System Initialization 310 mode.After all system initialization operations 310 have been completed themicro-controller 10 will instruct the SIR system to take a sensorreading and notify remote hardware and software systems and providepowered up status information and the results of an initial sensor 200reading.

Standby Mode 312—Standby mode 312 is intended as a transition modebetween sleep mode and active mode. During standby mode 312, onlynecessary operations such as powering up and enabling blocks areperformed before entering active mode. Once all the necessary setupoperations are complete the micro-processor will direct the system toenter active mode 314 where pre-defined operations are performed. Nodata processing or communications need to occur during standby mode 312.

Active Mode 314—During active mode 314 the sensor data is acquired andprocessed and any necessary setup required before performing long orshort haul communications is performed. During this active mode 314 themicro-controller 10 controls SIR block enabling and disabling sequenceso that the current consumed is minimized. For example, while the sensordata is being acquired, it is preferred that the other SIR blocks may bedisabled. Then, once the sensor data is acquired and processed, the SIP20 will be disabled and other related blocks will be enabled as neededto continue the flow of data. In the low power mode, it is preferredthat no wireless communication occur during this mode.

Communication Mode 316—The communication mode 316 is entered whenevershort/long haul communications are required. Currently this type ofcommunication is performed infrequently in order to conserve batterylife. The events where the communication mode 316 will be executed are;long haul communications, short haul communications, and retrieving GPSinformation.

Sleep Mode 318—The current consumed by the SIR device is the lowest forthe sleep mode 318 of operation. Only those blocks that are required forcontrol and interrupt detection will remain powered up. These blockswill be powered up but they will be in a low current sleep mode 318. Themicro-controller 10 continues to monitor interrupt signals and maintainRTC functionality while in sleep mode 318 and the accelerometer canstill detect movement while in sleep mode 318. Therefore, the systemmaintains the necessary functionality while minimizing the current drawnfrom the battery thereby maximizing battery life. The power supplies toall other blocks are disconnected to eliminate current consumption fromthese blocks while in the sleep mode 318. Before entering into sleepmode 318 the micro-controller 10 must set the pins states so thatcurrent consumption is not inadvertently consumed when the powersupplies are disconnected. For example, if one of the micro-controller10 outputs is driven high and is connected to an input of a powered downdevice, the device will consume current through the input protectioncircuitry. This could be a significant current draw so it is vital thatthe micro-controller set all pin states correctly before the deep sleepmode is entered.

Mode Transitioning—Moving from mode to mode depends on completing theprevious operation or receiving an interrupt. Time based interrupts areinterrupts that are predefined and are used to transition from oneoperational state to another. For example, the block power up time maybe used to set an interrupt that notifies the micro-controller 10 theblock has had sufficient time to power up and the next operation can beexecuted. The accelerometer interrupt notifies the micro-controller 10that the SIR has been moved. The micro-controller 10 will process thisinterrupt and initiate the necessary operations that results in sendinga notification message to remote hardware and software system. Theactual sequence of operations depends on the current operating mode.

The SIR also includes a strategy for conserving power. The SIR powerconservation strategy will employ disconnecting block power supplies andputting devices into sleep mode in order to minimize the currentconsumed by the SIR. Special care must be taken to control the blockinterfaces properly before the power supplies are disconnected. Allinputs to powered down blocks must either be driven low or tri-stated inorder to ensure the input protection diodes are not forward biased andconsume current. All inputs of powered up blocks being driven by outputsfrom an unpowered block must be disabled to prevent a floating inputfrom consuming unwanted current. The micro-controller 10 will set allblock interfaces so that these requirements are satisfied.

The SIR architecture and operation is customizable and particularly wellsuited to low power sensing applications. As an example of an exemplarysensing application, the SIR is deployed to monitor one or more assetsin an unpowered environment and isolated environment for a prolongedperiod. One or more sensors 200 are functionally coupled to the assetand each sensor 200 having a SIR compatible communication capability iscoupled to the SIR at one of the plurality of the sensor coupling ports25. Further, because different assets and environments may requiredifferent sensors 200, the coupled sensors 200 could be any variety ofsensors 200 such as temperature monitors, door monitors, voltagemonitors, current monitors, tank level monitors, or other sensors 200depending on the application and the asset and/or environment monitored.During SIR deployment, the SIR (i) operates a stored software process tosystematically initiate receipt of sensing data, or respond to sensordriven interrupts, via at least one of the sensors 200 coupled to asensor coupling port 25 and (ii) relays the sensing data to a remotelocation via wired or wireless communications and/or alternativelyresponds with a predetermined action based on programming stored withinthe SIR micro-controller 10 memory.

FIG. 5 illustrates a simplified logical block diagram of aspects of thearchitecture of the Sensor Interface Relay (SIR) that facilitatemultiple communication standards capability and power saving strategies.The preferred SIR includes at least one central processing unit coupledto memory, or more preferably, a micro-controller 10 in functionalcommunication with at least one Sensor Interface Port (SIP) 20. A SIP 20includes a plurality of uniquely addressable and programmable interfaces22 capable of functional connection and communication with themicro-controller 10; and peripheral sensor interface circuitry 23 thatconverts the programmable interfaces 22 inputs/outputs to preferredserial communications standards (e.g. RS232/RS485) common to sensors 200or to alternate sensor communications based on analog signals such as ACVoltage, Analog DC voltage and analog resistance. Associating each SIPinterface 22 and associated sensor interface circuitry 23 with a sensorcoupling port 25 enables the SIR to provide multiple sensor couplingshaving multiple communications capabilities and while employing powersaving strategies for the entire SIR system.

The SIR architecture facilitates power management strategies andselective power gating to turn on/off power to sensor ports 25 tominimize power consumption. For example, in certain sensingapplications, some sensors connected to the sensor ports 25 are notrequired to be on continuously. In such cases, the SIR architecture andimplementation allows powering down these sensor ports 25 and only turnsthem on when needed. The power management is independent for each sensorport 25 and can be programmed to turn on at different times furtheradding to the flexibility. But, in a typical sensing application, eachof the interfaces 22 and its associated sensor 200 will be sequentiallyenabled to receive sensor 200 readings and save power.

The SIP 20 is coupled to the 3V (nominally 3.3V) and 5V power suppliesgenerated in the SIR power systems block 4. The 3V and 5V supplies powerthe programmable interfaces 22 and peripheral sensor interface circuitry23 of the SIP 20, which in turn provides 3V and 5V power supply outputsoptions to power sensors 200 coupled to the sensor coupling ports 25.FIG. 11 shows more detail of the power switches and power multiplexers24 inside the SIP 20 block that are controlled by the interface 22sensor port configuration programming stored within firmware. Thisallows the SIR to interface with and power sensors 200 that requireeither 3V or 5V being applied to VCC1, VCC2, and VCC12 depending on theinputs EN1, EN2, and EN12 as shown in the truth tables 27 of FIG. 12.

The SIR and SIP 20 architectures allow multiple sensor coupling ports 25to be powered at the same time or more preferably for power-savings, theplurality of sensor coupling ports 25 are powered one at a time orsequentially. As one example, in a low power operation, themicro-controller 10 will wake, power up and program the SIP 20,sequentially perform sensor 200 readings, and then power down the SIP20. More particularly, and with reference to FIG. 5 and as shown in FIG.6., the micro-processor 10 will send a first enable signal (e.g.“PortAddrAll”) that powers all the sensor interfaces 22 with a singlesignal 212. The micro-controller 10 then uniquely addresses one of theplurality of interfaces 22 (using“PortAddr_(0 . . . n).”) 214 and sendsa second enable signal (“PortEn”) 216 common to all the interfaces 22.The combination of a correct unique address on common address lines(“PortAddr1, . . . , PortAddrn”) and second enable signal (“PortEn”)enables the selected interface 22 to subsequently enable 218 itsassociated power switches and power multiplexer 24 and subsequentlyinitiate programming 222 of the peripheral sensor interface circuitry 23to select or program the sensor coupling port 25 communicationcapabilities. The micro-controller 10 then will initiate communications224 with the coupled and associated sensor 200, and/or receive sensor200 readings, and relay it to a remote hardware and software system.After a sensor 200 reading is taken, the peripheral sensor interfacecircuitry 23 will be powered down and then the power switches and powermultiplexer 24 is also powered down. Any SIP that was powered by thePortAddrAll signal will be powered down if the PortAddr0 . . . n 214signals do not match the SIP's unique address when the PortEn 216 signalis sent.

Moreover, a plurality of third enable signals (e.g. “En1 . . . i”), oneeach respectively associated with each sensor coupling port 25, areavailable if needed based on the sensor 200 requirements. The pluralityof third enable signals provides the capability to interface withsensors that may perform a specific communication standard but alsoallows the interface to be enabled or disabled with a separate signal.For example, an analog sensor 200 or associated passive component mayrequire significant time to settle or reach a steady state condition. Insuch conditions, the SIR can assert a third enable signal, e.g. Eni, toenable/power up the sensor 200 and then subsequently employ the processillustrated in FIG. 6 and described above to uniquely address and enablethe SIP 20 and second enable signal, “PortEn”, to communicate with orread the sensor 200 previously enabled/powered by the third enablesignal. Yet another example of a sensing application using the thirdenable signal comprises a situation when a sensor is to be constantlypowered or powered for a significant time for optimum or proper sensoroperation. The third enable signal allows the SIR to power or enable theassociated sensor 200 only rather than also powering the SIP 20.

The hardware architecture of a preferred embodiment of the SIR, whichincludes the lower level block requirements for the various blocks inthe architecture, is illustrated in FIGS. 7 and 8. The preferredembodiment is implemented with several integrated circuits (ICs), eachhaving features facilitating certain functions or features of the SIP 20and implement switching, logic, and communications functions and sensorconnections. A preferred interface 22 of the SIP 20 embodiment includesa processing unit comprising an integrated programmable hardware andsoftware IC solution that may be implemented with any number of discreetor integrated solutions capable of the disclosed features required.Features and functions of the SIP 20 may be implemented in discrete ICsimplementing the various functions or in alternative solutions featuringhigher levels of integration such as Field Programmable Logic Arrays,Field Programmable Gate Arrays, or micro-controller based solutions suchas a Programmable System on a Chip (PSoC).

A preferred IC solution that accommodates the desired communicationscapabilities while minimizing power requirements includes a programmablecomputer system on chip (PSoC) 220 such as the Cypress SemiconductorCY8C5868, which performs many functions that include sequence ofoperations, digital and analog processing, and block power cycling. ThePSoC5 device includes a large number of programmable IO's, programmabledigital and analog resources, and it's interconnect matrix providesflexibility in connecting all resources together. The PSoC 220 includessupport for programming, testing, debugging, and tracing hardware andfirmware. Four interfaces are available: JTAG, SWD, SWV, and TRACEPORT.JTAG and SWD support all programming and debug features.

The SIP 20 interfaces with the micro-controller 10 and implements theprogrammable communications functions of the SIR as controlled by themicro-controller 10. Each of the sensor coupling ports 25 comprises anindependently configurable and operable sensor coupling port 25 that canbe configured in the field or at sensor deployment to work with aplurality of sensor electrical interfaces and communication standards.The SIR architecture also allows powering of the sensors 200 at any of,but not limited to, two different voltage levels. As a result, each ofthe sensor coupling ports 25 can be configured to a variety of sensorelectrical interface communication standards and sensor power supplyvoltages. The sensor coupling ports 25 are configured through a PortEnable command sent from the PSoC5 which contains the desired portsettings. These settings include voltage levels, pin drive modes,interrupt settings, protocol specific settings (addresses, clock speeds,baud rates), and any other relevant settings. These commands aretypically only sent at system startup but can be sent at any time.

The preferred SIP 20 implementation includes multiple micro-controllerbased interfaces 22 coupled to the micro-controller 10. Each interface22 in the SIP 20 couples to the micro-controller 10 and its associatedsensor interface circuitry 23 to communicate with at least oneexternally connected sensor 200 using at least one communicationstandard selected from, but not limited to, RS232; RS485; UART (CMOS);I2C; Open Collector; Open Drain; Maxim 1-wire; Analog AC voltage; AnalogDC voltage; Analog Resistance. The SIR architecture allows for theadoption of new communication standards based on the integralcommunication capabilities of the PSoC chosen for the SIP 20 and theavailable sensor interface circuitry 23.

The illustrated embodiment of an SIP 20 consists of four PSoC basedinterfaces 22 and supporting sensor interface circuitry 23 creatingeight sensor ports 25 (port 1 through port 8). Each interface 22controls and configures the power supply 24 and two sets of sensorinterface circuitry 23, each set connected to one sensor coupling port25. For example, a first PSoC based interface 22 controls ports 1 and 2,a second PSoC based interface 22 controls ports 3 and 4, . . . etc. Theinterface 22 signals that communicate directly with the micro-controller10 are: a plurality of port addressing signals (PortAddr0-2,PortAddrAll); port enable, reset, and interrupt signals (PortEN,PortXRES_n, PortIntr); UART signals (TX_in, RX_out, RS485_en); dedicatedsensor enable signals (EN1_in, . . . , EN8_in); a dedicated analogsignal line shared between the eight sensor ports 25 (Anal_IO); and JTAGsignals. The three port addressing signals (PortAddr0-2) permit eachPSoC based interface 22 to have a unique address. The interfaces 22share an additional common addressing signal originating from themicro-controller 10, PortAddrAll, that powers/enables every PSoC basedinterface 22 while the micro-controller 10 uniquely addresses one of theinterfaces 22 and enables one of the interfaces using PortEn to performa sensing operation through one of the plurality of sensor couplingports 25. The UART, analog, reset, and interrupt signals are also sharedbetween all ports. The address bits determine which sensor coupling port25 is communicating with the micro-controller 10 for various operations.The sensor data is communicated through the UART signals or the analogsignal. However, the UART interface is not limited to only communicatingsensor data. This interface can also be used to transfer configurationdata or other information between the micro-controller and the SIP.

The JTAG signals are used for programming and debug purposes. Thisinterface will be controlled by the micro-controller. The mainmicro-controller and the SIP micro-controllers have built-in JTAGprogramming circuits and provide JTAG pins to interface to a JTAGprogrammer device that is not part of the SIR. The JTAG programmerdevice plugs into the SIR via a JTAG port connector. The JTAG programmeralso interfaces to a PC through which the main and SIP micro-controllersare programmed.

Programming the micro-controllers includes loading the firmware or themain system control functions as shown in the state transition diagram.It also includes loading the configuration memory that is used toconfigure the SIP interface standard and other configurations for sensordata processing, analysis and long haul communications. Each SIP iscurrently programmed (either through JTAG or bootloaded through thediagnostic port) with the ability to support each of our currentcommunication protocols. Each port is initially configured to beunpowered and can dynamically configured for a specific communicationstandard by receiving commands from the PSoC5

The sensor coupling ports 25 connect directly to the sensors 200. Due tothe large number of communication standards being supported, a 12 pinconnector is required to interface between the sensor coupling port 25and the sensors 200. A sample sensor coupling port 25 to sensor pinbreakdown is as follows: 1 pin: 3V or 5V sensor power supply; 2 pins:sensor ground supply; 2 pins: CMOS UART TX & RX, I2C SCL & SDA, OpenDrain/Open Collector, CMOS, 1-Wire; 1 pin: Analog DC, Analog Res; 2pins: Analog AC2DC; 1 pin: Sensor enable; 3 pins: RS232/RS485 RX, TX/A,B.

The port signaling standard chosen is defined by the system application.Knowing the system application allows the sensor port configurations tobe stored in non-volatile memory within the SIP 20 so that it can beretrieved when needed. Each sensor coupling port 25 requires severalport controls to be properly configured. The micro-controller 10 doesnot have enough pins to control each port separately. Therefore, theindividual port controls are created inside the SIP block.

Sensor Interface Port Supported Signaling Standards—

The following section provides a brief description of the signalingstandards supported by the sensor coupling port 25.

UART (CMOS)—

This signaling interface is expected to be used as a CMOS version of theRS232 signaling standard. Some sensors have been found that specify anRS232 protocol but use CMOS signal voltage levels. The SIO PSoC3 outputsare used for the TX and EN outputs so that the output power supply canbe set to either 3.3V or 5V. The RX input is connected to a GPIO pinthat has a fixed 5V supply. If a 5V sensor is connected to the port theGPIO will be configured for CMOS operation. If a 3.3V sensor isconnected the GPIO input buffer will be configure for TTL input levels.

RS232 and RS485—

These standards are the real RS232/RS485 signaling standards. Acomponent has been identified that converts a UART signal to RS232/RS485levels. The component includes dual RS232 and RS485 transceivers so onecomponent will be used for 2 sensor ports. Sharing a single deviceacross two ports requires special handling to ensure the powered downport does not cause unexpected performance. The architecture takes thisinto account so no unexpected operation will occur. LTC2872 from LinearTechnology is used to convert CMOS UART signals to RS232/RS485.

Analog Resistance—

The analog resistance communication simply implies that the sensor actsas a variable resistance. This type of sensor is read by applying avoltage to one end of the sensor and connecting the other end to anop-amp configured to detect the external resistance of the sensor. Theop-amp output voltage corresponds to the current flowing through theresistive sensor. The op-amp output voltage is fed to the ADC where theoutput is translated to a specific resistance value. The PSoC devicecontains an op-amp and an ADC to perform the necessary operations.

Analog DC and AC-to-DC Voltage—

These signaling standards are similar to the analog resistance standardexpect the op-amp is not required to create the ADC input voltage. Forthe analog DC signal the sensor produces the DC voltage level that isinput to the PSoC5 ADC. The analog AC-to-DC signal is similar except anAC-to-DC converter component is used to convert the sensor generated ACvoltage level to a DC voltage level before the ADC performs thetranslation.

Open Collector/Drain—

The open collector/drain signaling standard is implemented byprogramming the PSoC3 IO as a weak pull-up. This configuration places a5 kOhm resistor in series with the pull-up driver which meets the opendrain requirement.

Similar to the UART standard this standard is connected to an SIO pin sothe supply level can be set to either 3.3V or 5V depending on the sensorsupply level.

I2C—

The I2C signaling standard is similar to the open drain standard exceptfor the pull-up resistance value. The PSoC3 device includes special I2Cpins that implement the I2C protocol. External resistors must be placedon these pins in order to fully implement the standard. The power supplyto these resistors can be set to either 3.3V or 5V in order to match thesensor supply.

FIG. 7 shows the contents of the SIR_PortX2 block shown in FIG. 6. Thecomponents contained within this block are: PSoC3 device; Power switchblock; Analog RMS2DC converter; RS232/RS485 transceiver; Analog muxes;and I2C pull-up resistors.

The PSoC3 device controls the sensor coupling port 25 operation. ThePSoC3 contains the firmware and the port configuration programming sothat a ports associated sensor peripheral interface circuitry 23 can beset so a sensor 200 reading can be performed correctly. The power switchblock 24 is composed of switches and muxes that supply the correctlevels to the sensor and the port circuitry. The RMS2DC converter isused for sensors that output an AC waveform. This AC signal is convertedto a DC voltage level that is passed through an analog mux to themicro-controller where the level is sensed and processed. The analogmuxes are also used to pass analog DC levels to the micro-controller forprocessing. The RS232/RS485 transceiver converts CMOS signals to eitherRS232 or RS485 format so the SIR can communicate with sensors usingthese communication standards. The PSoC3 device has specific pins thatcan be used for I2C communication. Pull-up resistors have been added tothese pins and the port configuration is used to configure these pinsfor I2C when needed. The PSoC3 can also directly perform UARTcommunication with sensors using this standard. For those standards forwhich the PSoC3 can directly communicate with the sensor, the data isreceive by the PSoC3 is passed to the micro-controller through the UARTinterface between these blocks. Currently, there is no plan to processthe data within the PSoC3 before passing it to the micro-controller.However, the pre-processing capability does exist with the PSoC3 deviceand may be used is deemed necessary.

The SIP 20 architecture has been designed so that only the circuitryrequired to perform a reading is powered up. This scheme saves onbattery life but requires special timing between signal activation. Thefollowing items must be ensured in order for this scheme to workproperly: (1) the blocks must be powered up prior to taking a reading;(2) the control signals must be set appropriately before and after ablock is powered up; and (3) the blocks must be powered down aftertaking a reading. The port control signal truth table is shown in in thetruth table of FIG. 9. The table contains the following information:Port mode; Port number and power supply level; Port power switch controlsignals; Communication standard control signals; and Data signals. Thetruth table illustrates the how the SIP 20 sequentially enables thepower switches and power multiplexer 24 and programming of the sensorinterface circuitry 23 (i.e. steps 218-224 of FIG. 6), after the SIP 20associated with sensor coupling ports 1 and 2 is uniquely addressed andenabled (i.e. steps 210-222 of FIG. 6).

The port mode refers to the communication standard configured for thedesired sensor coupling port 25. The port mode also includes the powerdown state. The port number specifies which sensor coupling port 25 isactive. The power supply column specifies the sensor power supplyvoltage. The power switch enable control signals selects the powersupply level applied to the sensor and the corresponding portcomponents. The communication controls select the desired communicationstandard. The data signals specify the state of the pins for eachstandard.

The following describe the entries in the table: 1 & 0: High and lowvoltage levels; 10 or 01: Signal can be in either state but bit statescorrespond to each other (e.g. if DXEN1=1 then RXEN1_n=0); Z: Tristateoutput drivers or disable input buffers; D: Data can transition; andWPU: Driver is configured as a weak pull-up and strong pull-down.

The sensor coupling port 25 always starts and finishes in the power downstate. The table columns have been grouped to denote a timing sequencerelationship. The sensor coupling port 25 starts in the power downstate. If the sensor coupling port 25 is selected the power switchcontrols will be activated when the PortEN signal is activated. Thiscauses the power supply voltages to be selected and the correspondingcomponents are powered up. Note that the other signals will not changefrom the power down state until the components have finished poweringup. The power up time will be set by the component requiring the longesttime to power up and initialize. This information is gathered from thecomponent datasheets to become a variable in the firmware in the SIP 20.Once power up is complete the communication controls will be switched bythe SIP 20 via UART signals sent from the first processing unit to statemachines within the SIP firmware depending on the communication standardconfigured. After the communication controls have switched a sensorreading is performed. Once the sensor reading has been taken thecommunication controls are switched back to the power down state. Afterthe communication controls have reached their power down states thepower switch controls are set back to their power down state. At thispoint the SIP 20 is back in the power down mode and ready to performanother sensor reading.

The sequence described above applies when the SIR device is operating onbattery power. If the SIR device is powered from an external source thepower switch controls and the communication controls can remain activefor all the sensor coupling ports 25. For this situation the portaddress selects (“PortAddr_(0 . . . n)) which sensor coupling ports 25will be read and the port enable signal (“PortEn”) initiates the readingwhen activated and terminates the reading when deactivated.

Currently the SIP 20 supports the communication standards listedpreviously. However, the architecture has been designed to utilize anexpansion board to accommodate more standards in the future. Anexpansion board is a separate board that can be plugged onto theexisting board and replaces an existing sensor port. The port expansionboard will contain the necessary components to perform the desiredcommunication standard and the original sensor port will be used tocommunicate the port expansion board reading to the micro-controller. Inother words, the port expansion board will appear as a sensor beingconnected to the main board. The UART communication standard will beused to communicate between the main board and the expansion board.

The expansion board scheme will be implemented by providing headers onthe main board that ship the necessary signals to the expansion boardwhen it is plugged into the main board. The original sensor port PSoC3device has additional control signals dedicated for the expansion board.The port expansion board control signals will only be functional if theport expansion board exists. This scheme will allow future communicationstandards to be employed without requiring a major redesign to the mainboard.

Once the sensor data is received by the sensor port 25 via the sensorinterface circuitry 23, the sensor interface 22 architecture routes thesignals through appropriate signal conditioning circuits before sendingthem to either digital or analog processing blocks. In the digitalprocessing unit the sensor data is extracted and in the analogprocessing unit the sensor data is digitized. A central processing unitthen receives the digitized sensor data from both the analog and digitalprocessing units and performs further analysis before communicating itto the remote location.

In addition to supporting a dozen or more sensor interface standards,the architecture is flexible by providing options to expand support foradditional sensor interfaces. It does so by allowing addition oftranslation blocks to convert new sensor interfaces to one of thesupported interfaces. With this capability, support for new sensorinterfaces is almost limitless. This expansion happens at the peripheryof the sensor interface without impacting the core architecture. This iscritical in allowing the base architecture to remain unchanged for awide variety of Internet of Things (IoT) applications, enabling a quicktime to market.

In some applications wireless sensors are a more practical method ofmonitoring an asset in spite of the high cost and power. In such casesthe sensor data is transmitted over a radio communication channel to areceiver. Typically the receiver demodulates the message into digitalform and sends it over a serial interface to a processor. The SIRarchitecture supports some of the common serial interfaces like RS232,RS485, UART etc. This enables the SIR to physically interface with anexternal radio module to receive the wireless sensor data.

Functional Description of the Cellular Radio—

The cellular radio is intended to perform long haul communications. TheJanus cellular module HSPA910CF that includes the Telit HE910 cellularchip has been chosen for the SIR device although the provider of thecellular radio should not be limited to a single version or provider.Other embodiments using alternate radios may be accomplished using thesame implementation. The communication between the PSoC and the cellularmodule will be performed through a UART connection. This communicationstandard has been chosen since the PSoC5 device does not include a USBhost which is required for USB communication with the cellular module.

The PSoC5 has a limited number of pins allotted to interface with thecommunication modules. The SIR architecture includes a multiplexor thatmultiplexes the Cellular, GPS, POTS, and ZigBee modules signals tospecific PSoC5 pins. If the cellular module is not required themultiplexor will be used to connect a separate GPS module and ZigBeemodule to the same PSoC5 pins. Similarly, if the SIR requires POTScommunication the cellular module will be replaced with a POTS moduleand the POTS signals will be muxed to the PSoC5 device.

The cellular radio consumes a large current when transmitting and is notdesigned for low current consumption when disabled. Therefore, thecellular radio may be powered down when it is not required forcommunication. The PSoC IO's interfacing with the cellular radio must beeither driven low or tri-stated when the cellular radio is powered downto prevent the ESD protection devices on the pin from forward biasingresulting in large unwanted current to flow.

Signals—

Only required pins are denoted as being connected to the PSoC device.These pins include the UART signaling pins and enable type pins.

ZigBee Radio—

The ZigBee radio will be used to perform short haul communications. Thearchitecture currently allocates pins for the ZigBee radio. The pinsallocated are based on using UART communication between the module andthe PSoC.

Functional Description of the GPS Radio—

The SIR architecture currently provides a slot for a separate GPS radio.The cellular module also includes a GPS radio. The GPS located on thecellular radio is expected to be used and a separate GPS radio modulewill be placed on the board when the cellular radio is not placed on theboard. The cellular and separate GPS radios are multiplexed onto thesame PSoC pins since they are not planned to be used at the same time.

The FRAM is a ferroelectric nonvolatile RAM. It performs read and writeoperations like a standard RAM and does not have the overhead associatedwith standard serial FLASH memories. The intent of this memory is tostore sensor data and unsent messages in an advent that the SIR power islost or issues exist such that the SIR cannot communicate with theremote hardware and software system. The SPI bus will be used to readand write data between the micro-controller and the FRAM.

A Lithium-Ion battery is currently planned to be used to power the SIRdevice. The following sections describe the assumptions and provide abattery life estimate based on these assumptions.

Assumptions—

The operating conditions for meeting the 2 year battery life requirementare left up to design. The current operating assumptions used toestimate the battery life are as follows: A maximum of 2 cellularcommunications are performed per day (the total cellular transmissiontime is 3 seconds per transmission and includes any GPS communicationsthat may occur); the SIR device will perform sensor readings every 30minutes; all devices expect the micro-controller, micro-controllerregulators, and the accelerometer are power-down (power supplies aredisconnected) when the SIR device is not performing operations; and thebattery life calculations assume 85% of the rated battery mAh to accountfor inefficiencies in the power system design and an additional 15%derating due to battery self-discharge.

Calculations—the battery life estimates are enhanced by separateoperating modes. The time spent in each mode is based on the assumptionsin the previous section and the current consumed in each mode isestimated.

Sleep Mode—during sleep mode all components will be powered down exceptthe micro-controller and the accelerometer. Since the SIR device willpredominately be in sleep mode the time estimate for this mode is set to2 years. The sleep mode effect on battery life is summarized in Table15.

Standby Mode—during standby Mode all the powered down devices arepowered up. Only the components that will initially perform operationsare enabled during this mode. The components that are enabled duringthis mode are the micro-controller and the serial interface port. Allother components are powered up but remain in a low current consumptionmode.

Active Mode—during active mode all the blocks are enabled and the sensorreadings are performed and processed. The active mode effect on batterylife is summarized in Table 17.

Comms Mode—During communication mode the micro-controller communicatesto the cellular radio and the cellular radio communicates to remotehardware and software. Most of the other blocks in the SIR device arepowered down to conserve battery life.

While various embodiments have been described, those skilled in the artwill recognize modifications of variations that might be made withoutdeparting from the present disclosure. The examples illustrate thevarious embodiments and are not intended to limit the presentdisclosure. Therefore, the description and claims should be interpretedliberally with only such limitation as is necessary in view of thepertinent prior art.

We claim:
 1. A method of obtaining inputs from a plurality of sensorcoupling ports, comprising the steps of: from a first processing unit,communicating a state change on a first common addressing signal coupledto each of a plurality of second processing units and uniquelyaddressing one of the plurality of second processing units on at leastone additional addressing signal; communicating from the firstprocessing unit to each of the plurality of second processing units asubsequent state change on a common enable signal line coupled to eachof the plurality of second processing units; detecting the state changeon the first common addressing signal, the unique addressing, and thesubsequent state change on the common enable signal line in one of theplurality of second processing units; and communicating from the firstprocessing unit to the one uniquely addressed second processing unit toreceive an input to the first processing unit from the sensor couplingport.
 2. The method of claim 1 wherein, uniquely addressing one of theplurality of second processing units further comprises the step ofaddressing over a plurality of addressing signals respectively coupledto each of the second processing units.
 3. The method of claim 1 furthercomprising the step of, communicating configuration information from theuniquely addressed second processing unit to a sensor interface circuitthat communicates over the sensor coupling port in a standard selectedfrom RS232, RS485, UART, Open Collector, Open Drain, I2C, Maxim 1-Wire,Analog AC voltage, Analog DC voltage, Analog Resistance, CMOS, or TTL.4. The method of claim 1 further comprising the step of, eliminatingpower from any non-uniquely addressed remaining plurality of secondprocessing units.
 5. The method of claim 1 further comprising the stepsof, uniquely addressing a second of the plurality of second processingunits, subsequently initiating a state change on the common enablesignal line coupled to each of the plurality of second processing units,and detecting both the unique addressing and the subsequently initiatedstate change on the common enable signal line in the second of theplurality of second processing units, and communicating from the firstprocessing unit to the second uniquely addressed second processing unitto receive input from the second sensor coupling port.
 6. The method ofclaim 5 further comprising the step of, communicating configurationinformation from the second uniquely addressed second processing unit toa second sensor interface circuit that communicates over the secondsensor coupling port in a standard selected from RS232, RS485, UART,Open Collector, Open Drain, I2C, Maxim 1-Wire, Analog AC voltage, AnalogDC voltage, Analog Resistance, CMOS, or TTL.
 7. The method of claim 1further comprising the step of, sourcing a sensor power supply signal toone of the plurality of sensor coupling ports prior to communicating thestate change on the first common addressing signal.
 8. The method inclaim 1 further wherein, the plurality of sensor coupling ports areunpowered and communicating a state change on a first common addressingsignal after receipt of an interrupt from at least one of the sensorcoupling ports.
 9. The method in claim 1 wherein, the plurality ofsensor coupling ports are unpowered and communicating a state change ona first common addressing signal is initiated at programmed intervals.10. The method in claim 1 wherein, the sensor coupling port communicateswith a standard selected from RS232, RS485, UART, Open Collector, OpenDrain, I2C, Maxim 1-Wire, Analog AC voltage, Analog DC voltage, AnalogResistance, CMOS, or TTL.
 11. The method in claim 10 further comprisingthe step of, enabling a circuit to communicate with a standard selectedfrom RS232 and RS485.
 12. The method in claim 10 further comprising thestep of, enabling a circuit to convert root mean square readings to DCvoltage readings and communicating the DC voltage readings to the firstprocessing unit.
 13. The method in claim 1 further comprising the stepsof, eliminating power to the plurality of second processing units andtransmitting the input to at least one remote hardware and softwaresystem; and placing the first processing unit into a standby mode. 14.The method of claim 1 further comprising the steps of, eliminating powerto the plurality of second processing units and transmitting the inputunder a selected set of conditions to at least one remote hardware andsoftware system; and placing the first processing unit into a standbymode.
 15. The method in claim 1 wherein, the communication is selectedfrom Cellular, ZigBee, and POTS.